macmahon



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M. M40 MAHQN. COMPOUND STEAMl ENGINE.

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(No Model.) 4 Sheets-Sheet 2.

M. MAG MAHON.

GoMPoUND STEAM ENGINE.

No. 247,994. L Patented'Oot.. 4,188.1.

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M.l MAC MAHO'N.

GOMPOUND STEAM LiNGfINE-l I No.l 247,994. .l Patented Oct. l4, 1881.

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(No Model.) 45mm-sheet 4.

M. MAG M'AHON..

. v GOMPOUND STEAM ENGINE.` No. 247,994.l f Patented 001;.`4,1881.

UNITED STATES PATENT OEEICE. V

MIOHEAL MAG MAHON, OF BROOKLYN, NEW YORK, ASSIGNOR TO JAMES W. GHISHOLM, TRUSTEE, OF SAME PLACE.

coMPouND STEAM-ENGINE.

SPECIFICATION forming part of Lettersilatent No. 247,994, dated October 4, 1881. Application filed December 3, 1880. (No model.)

To all 'whom it may concern Be it known that I, MIGHEAL MAC MAHON, of the city of Brooklyn,connty of Kings, State of New York, have invented certain new and useful Improvements in Compound Steam-Engines, of which the following is a specification.

This invention has for its object to increase the efficiency of compound steam-engines by more fully utilizing the steam and obviating loss of temperature from radiation of heat. This desirable result I accomplish by a novel construction and arrangementof three doubleacting cylinders, each having independent slidevalves, the steam from the boiler being admitted only to thesmallestof the three,which is the high-pressure cylinder, and which is centrally located in the second or intermediate cylinder. This intermediate cylinder is provided with an annularpiston having two piston-rods connected to the same cross-head as the high-pressure piston-rod. The steam, after actuating the piston of the high-pressure cylinder, passes through a valve-chest and into the intermediate cylinder, from which, after further expanding and actuating the annular piston, it escapes into a receiving-chamber, andfrom this chamber,inwhich the slidevalve of thelow-pressure cylinderis placed, the steam passes into the third or low-pressure'cylinder, and then through an ordinary exhaust-pipe to asurface-condenser, which may be of anyof the ordinary constructions. The crank to which is connected the piston of the lowpressure cylinder and tho crank to which is connected the pis. tons of the high-pressure and of the interlnediate cylinders may be set at any desired angle relatively to each other on the main shaft. The second and third cylinders are surrounded by steamgackets. The second cylinder forms a steam-jacketfor the rst, and all of the exterior surfaces are covered with any suitable non-conductorofheat. Thereceiving-chamberbetween the second and third cylinders is provided with a series of pipes horizontally arranged within it, through which some of the heat from the furnace is allowed to pass, thereby reheating the steam in this chamber and preventing condensation taking place, as well as re-evaporating the water in the steam, should any-be formed.

The casings of this chamberare provided with 5o suitably-placed doors, to afford opportunity for cleaning thetnbes.

The invention also consists `in a novel arrangement of the steam-chests and steam-passages, and of the application of puppet-valves to the slide-valves of the high-pressure cylinder, which puppet-valves are operated by av new and simply adjustable cut-off mechanism,

all of which will befullydescribed byreference had to the accompanying drawings, forming 6o part of this specification, in which- Figure 1, Sheet 1, is a longitudinal sectional elevation of my improvelnents in compound steam-engines. Fig. 2, Sheet 2, is an end elevation, showing the covers of the steam-chests removed. Fig.3, Sheet 3, is a plan View of the cylinders, with the high-pressure and intermediate cylinders partly in section, through the line w fw, Fig. l. Fig. 4, Sheet 3, is a plan View ofthe general features of the engine, with the 7o cylinders in section, cut through the line x a',

Fig. 1. Fig. 5, Sheet. 4, is a transverse sectional elevation of thelow-pressuresteam-chest through the line y y, Fig. l. Fig. 6, Sheet 4, is an enlarged view of one of the high-pressure slide-valves, with its puppet cut-off valve and mechanism for operating the same partly in section. Fig. 7, Sheet 4, is a plan view of the same, also partlyin section 3 and Fig. 8, Sheet '4, is an end view of the cut-off device in sec- 8o tion through the line z z, Fig. 6. v

The form of Aengine shown in the drawings embodying my improvements is ofthe vertical inverted-cylinder type.` The high-'pressure cylinder a. is centrally located in the intermediate cylinder, b, which is in line with and on the same horizontal plane as the low-pressure or condensing-cylinder c. The piston c of the central cylinder, a, is connected byjits rod a2 with the cross-head d, as is also the'annular 9o piston b of the cylinder b by its two pistonrods b2 b2, and the piston-rod c2 of the lowpressure piston c connect-s it to the cross-head e. These cross-heads d and e are fitted to slide in guides, and are connected, respectively by the connecting-rods d and e', to their cranks d2 and e2 of the main shaft d3, in the ordinary manner. The two cranks are shown in the drawings as set diametrically opposite each other. They may be set in any angular position wit-hout affecting my improvements.

j'represents the condenser in communication withthe low-pressure cylinder c by means of theexhaust-pipef, and g is the air-pump, Suc., operated from the cross-head @by means of the rods and levers g g2; and as there is nothing particularly new in the construction and a rl rangement ot' these parts of the engine it is unnecessary to more fully describe them.

The steam-chests ot' the high-pressure cylinder c and intermediate cylinder, b, are located on the side of the rylinderb. The steamchest 7L of the intermediate cylinder, b, is between the two steam-chests t' andj of the highpressure cylinder a. Live steam from the boiler enters onlyT these two steamchests tand j through the pipe k, Figs. 2, 3, and 4, and passageways ha k, Figs. 3 and 1, connecting them together, and passes into the cylinder c alternately to the upper and lower sides of thc piston a through the. valves t" and j, which are ofthe ordinary slide-valve pattern, but are each provided with a puppet cut-oft' valve, to be hereinafter described.

The slide-valves i and j are operated by the rod k', which is connected to them by adjusting-nuts, and it passes loosely through a pipe, h6, Fig. 1, which is especially provided for the purpose, being cast into the walls of the ports ot' the intermediate cylinder, being as a pas sage-way for the rod and also to brace the walls of the ports and ljoin the two steam chests i andj, and the rod passes through a stuffinghox in the lower ehest,j, to the link k2. This link k2 also carries the rod h2, which passes up through astufting-box and pipe,h7,in the chest j, and is connected to the double-ported slidevalve h', and has necessarily the same travel as that ofthe high-pressure valves t and j.

The link k2 is operated by means ot' two eccentrics and their rods k3 kt, as generally adopted to constitute the operating part of the reversing-gear; and the link lafl is connected to the reversing-wheel h5 through the medium of its screw-shaft fitting in a nut pivoted to a lever, k6, which lever is secured to a shaft, k1", working in bearings on the back of the condenscrf, and the two rods k7, pivoted to a plate at the end of the lever k6 and to the center or" the upper and lower sides of the link k2, thus applying an even strain on the link when it is moved to allow either of the eccentries k3 or k4 to operate the valves; and this construction also admits of the ends of the rods ci k7 passing between the connection ot' the two valverods 7c and h2 with the link k2.

The shaft km, Fig. 4, to which the lever k is secured, extends along the rear of the condenserf, and has also secured to it the lever l, which is connected by the rod l to the link l2, Fig. l, forming the connection between the eccentrics and their rods t3 and Z4 and the valverod m of the slidevalve m', which is of the same construction as the slide-valve h', and it is located in the steam chest or receiver m2 of the low-pressure cylinder c. This steam-chest m2 is a large chamber between the cylinders b and c, and is formed on the exterior of the cylinders by casings or jackets b3 and c, Fig. 4.

Extending laterally through the chamber m2 is aseries of pipes, m3, which open into chambers formed at the sides of the chambers m2 by plates m4 m4 and flanges m5 m5, Figs. 3, 4, and 5, projecting from the sides ofthe chamber m2, and so arranged that the heated gaseons products of combustion from the smokestack entering through a connecting-pipe the opening in are caused to traverse the whole lengths of the pipes mi nr" back and forth before they pass away` through the opening mi, as shown at Fig. 5. These plates m1 m4 are provided with doors m8, suitably arranged to afford facilities for cleaning the tubes m3, and these plates, as well as the valve-chests and cylinder-heads, are covered with some suitable non-conductingmaterial. Thecylinder-heads may also be cast hollow, to further provide against loss ot' heat.

By the arrangementof thereceiver m2 above described some of the waste heat of the furnace is utilized to relient and prevent the steam in the chamber from condensing, so that it may pass into the low-pressure cylinder c in a better condition for use tha-n if allowed to pass therein after actuating the piston of the intermediate cylinder, Z, without being subjected to such extra heating and the reevaporation of e the water carried by it.

The puppet cut-off valves on the backs or" the slide-valves fi and j of the higlrpressure cylinder a and their operating mechanism are alike in every respect as regards construction and operation, but are reversed in position, as shown at Fig. 2, so that the following' description of the upper one, as shown in the enlarged views, Figs` 6, 7, and S, will answer for both of them.

On the back of the slide-valve t" is formed the open-end cylindrical chamber n, connecting the inlet-port of the valve to the interior of the steam-chest t. The ends of this chamber n are closed by the double puppet-valve u u', and the ends of its stem fit between the two arms a2 a2, secured to the shalt n3, so that there is no end-play, but with sufficient freedom to slide up and between them, so that the puppet valve n is not affected by the sliding action of the slide-valve t. The valve n' is opened and closed at the desired times, irrespective of the movement ot' the slide-valve fi', by motion being imparted to the shaft n3, which is done in one direction to close the puppet-valve by the spring n", held in the bracket a5, and surrounding the part ot' the shalt a3 which projects through a stuftng-box on the side of the stearnchest t'.

A collar on the shaft n3, against which the` spring a4 bears, carries a spring latch or tappet, n, which is constructed so as to be held by its spring at a horizontal position, as shown, and operated as hereinafter described.

The vertical shaft 0 is fitted to slide in the IIO brackets ni a5, and is connected to the rod p of the eccentric p. On it are secured the two adjustable cut-off devices, which consist of a carrier,.o, having an inclined projection, o2, occupying a given part of the throw ot' the ecceutric p', which in the drawings is shown as being one-fourth.

A series otrectangular slides, o, are litted in a slot in the carrier immediately under-the inclined projection o2, and adapted to be pushed out'in line with it by means of a cam, o4, having as many sections as there are slides, the rises ofthecam-sectionsbeingangularlyplaced, so that the top one is the iirst to act and the bottom one the Vlast to act on their respective slides, but they all drop off in one line, so that any number ot' the 'slides o3 may be moved and held out by turning the cam o4 the required amount; or all of the slides may he moved back ush with the side of the carrier o', leaving' the incline o? as the only projection, thus determining the length ottime the puppet-valve is to be held open, it being opened by the inclined projection oZ acting against the tappet n@ as the shaft moves in an upward direction, and it is so held open until the top edge ofthe tappet n passes over the lower edge of the incline o2, or the lower edge of the lowest slide o3, which has been pushed out by the cam o4. In the drawings two slides are shown as pushed out, the cut-oft' in this case taking place at onehalt' stroke, as each ot' the slides represents oneeighth of the stroke and the inclined projection o2 one-quarter. Ofcourse thenumberot' slides and the proportion each one bears to the stroke may be varied as desired. When the shafto is moving downward after the slides have passed over the tappet and the shaft n3 has been thrown back to close the puppet-valve by the spring a4, then the bottom ofthe inclined projection 02 or ot' the 'slide in use comes in contact with the top of the tappet a6 and moves it down out of the way against the action of its spring, allowing the slides and projection to pass without disturbing the shaft n3.

lhe cam o4 is designed to be turned around by the milled head on the upper end of its shaft, and to be held in any desired position by the spring-catch o5 falling into one of the holes in a collar on the cam, and the slides 03 are securely held in either position by a web ou the lever fitting into notches formed in their sides. The lever oG is prevented from moving out ot' the notches in the slides by means ot' a spring-latch.

The high-pressure and annular pistons a and b are represented in the drawings as just about to complete their upward'stroke. The projection 02 is about to act on the tappet nG to move the puppet-valve, sc that this valve is open when the pistons reach the upper ends of their cylinders and before the slide-valve t" has uncovered the port 2 to let the steam pass through the passage formed in the cylinderhead into the cylinder a, above its piston a. The slide-valve j' has opened the exhaust-port j2before the pistons reach the end of the stroke,

allowing the steam which had forced the piston a in an upward direction to pass through the passage j into the steam-chest h., and through its inlet-port h3 to the top ot' the piston b', the under side ofthe piston b exhausting through the passage h4 into the interior of' the valve hf, and out through the opening h5, around the outside of the cylinder b into. the chamber m2, from which it passes into the lowpressure cylinder c through the port r, the upper part of the cylinder o being now open to the condenserf through the passage r and eXhaust-pipef. Just bet'ore the pistons have completed their strokes live steam is let into the cylinder ct under the piston a from the steam-chestj through the passage js, the upper part ot' the cylinder a then exhausting intothe chest h through the passages i2 and i3. Steam from the chest h now passes to the under side of the annular piston b through the passage h4. The upper part ot' the annular cylinder b at the same timeis open to thecham her m2 through the passages h3 h5. The low-pressure cylinder c is now taking steam from the chamber m2 at its upper part.

From this. construction and arrangement of the various parts it will be seen that the live steam l'rom the boiler in performing its work in the cylinder a is protected from radiation bythe steam in the intermediate cylinder, b, which, in its turn, is protected by its own eX- haust-steam filling the space betu een thecylinder b and jacket b3 and the chamber m2, the cylinder c also beipg protected by this steam, which is iurther heated by the'gases of combustion passing through the pipes m3.

It is obvious that some of the improvements before described may be applied to steam-engines separately-as, for instance, the puppet cut-off valve, in combination with the slidevalve, and the reheating-pipes passiu g through the steam-chest of the low-pressure cylinder, and also the arrangement of the valves and valve appurtenances in the steam-chest h and between the steam-chests z' and j.

l do not-here claim the improvements shown and described relating to the puppet cut-oft' valve, as such will form the subject-matter of another application.

Having now described my invention, what I claim, and desire to secure by Letters Patent, 1s

1. In combination, the high-pressure cylinder ct and its pistou ot', the cylinder b and its annular piston b', the high-pressure steamchests and j, slide-valves i and j', and the intermediate steam-chest, h, and valve h', substantially as and for the purpose hereinbefore set forth.

2. In combination, the high-pressure cylinder a and its pistou a', the cylinder b and its annular piston b', the high -pressure steamchests i and j, connecting-pipe h6, slide-valves t" and j', and the intermediate steam-chest, h, and valve h', substantially as and for the purpose hereinbefore set forth.

3. The cylinder b, piston b', and pistou-rods b2 b2, connected to the cross-head d, in combination with t'ne cylinder a, the piston a', and its rod d2, also connected to the cross-head d, with their respective slide-valves and steampassages, constructed and arranged substantially as and for the purpose set forth.

4. In a compound steam-engine, in combination, the high-pressure cylinder a, located centrally within the intermediate cylinder, b, the intermediate cylinder, b, the low-pressure cylinder c, and the stea x11-chamber m2, connecting the cylinders b and c and partly or Wholly surrounding them, substantially as and l'or the purpose hereinbefore set forth.

5. In a compound steam-engine, in combination, the high-pressure cylinder a, valvechests i and j and their valves t" and j', the intermediate cylinder, b, valve chest l1, and valve h', the low-pressure cylinder c, and the steamchamber m2, connecting the cylinders b and c, and partly or wholly surrounding them, substantially as and for the purpose hereinbeiore set forth.

6. In combination with the steamchamber m2, located between and connecting the cylinders b and c, the pipes m3 m3, arranged substantially as described and adapted to act as lues, through which heated gases from the smoke-stack or furnace are caused to pass, as and for the purpose hereinbefore set forth.

7. In combination with the links k2 and eccentrics 7c3 7a4, the valverod It', carrying the two high-pressure valves i and j', and the rod h2, carrying the valve h of the intermediate cylinder, b, substantially as hcreinbcfore set forth.

8. The cutoff device composed ot' the vertically-moving shaft 0, carrier o', having inclined projection 02, slides o, adjusting-cam o4, spring-latch o5, and the horizontally-moving shaft n3, provided with the spring-tappct u and spring n4, all constructed and combined substantially as and for the purpose hereinbefore set forth.

9. As an improvement in compound steamengines, in combination, the high-pressure cylinder a., intermediate cylinder, b, low-pressure cylinder c, receiving-chamber m2, reheatingpipes m3 m3, valve-chests t', j, and h, valves t" and j', connected to link k2 by rod 7d, valve h, also connected to link k2, rods k7, arm ks, hand-wheel k, eccentrics and rods k3 7c, shaft 7c, rods and link Z l Z2, and valve m', eccentrics and rods Z3 Z4, cross-head (I, and pistons a and b', cross-head c and piston c', connecting-rods d and c,and double-crank shaftd, constructed and operated substantially as and for the purpose set forth.

In testimony whereof I have hereunto set my hand this 2d day of December, A. D. 1880.

M. MAC MAHON. Witnesses:

H. D. WILLIAMS, ALFRED SHEDLOCK. 

